ell.conj: Find conjugate axes or tangent lines to ellipse
In p3d: Plot 3d data and fitted surfaces

Description Usage Arguments Details Value Author(s) See Also Examples

Find conjugate axes or tangent lines to ellipse

1	ell.conj(center, shape, dir, radius = 1, len = 1)

`center`	center of the ellipse
`shape`	shape matrix of the ellipse
`dir`	a vector specifying a direction along which to find conjugate axes or tangent lines
`radius`
`len`

None yet

Returns a list with the following components

`u`
`v`
`tan1`
`tan2`
`tan3`
`tan4`
`center`	ellipse center

Georges Monette

uv

##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function( center, shape, dir, radius = 1, len = 1) {
            # returns conjugate axes or tangent lines to ellipse
            vecs <- uv( shape, dir, radius)
            list( u = list( center-len*vecs$u, center+len*vecs$u),
                  v = list( center-len*vecs$v, center+len*vecs$v),
                  tan1 = list( center + vecs$u - len*vecs$v,center + vecs$u+ len*vecs$v),
                  tan2 = list( center - vecs$u - len*vecs$v,center - vecs$u+ len*vecs$v),
                  tan3 = list( center + vecs$v - len*vecs$u,center + vecs$v+ len*vecs$u),
                  tan4 = list( center - vecs$v - len*vecs$u,center - vecs$v+ len*vecs$u),
                  center = center)
    }